This invention relates to a method for recording and reproducing images of objects made by penetrating radiation. It, relates especially to the recording and reproduction of images obtained by penetrating radiation in the field of medical diagnosis and in the field of non-destructive testing.
In a conventional radiographic system an X-ray radiograph is obtained by X-rays transmitted image-wise through an object and converted into light of corresponding intensity in a so-called intensifying screen (X-ray conversion screen) wherein phosphor particles absorb the transmitted X-rays and convert them into visible light and/or ultraviolet radiation to which a photographic film is more sensitive than to the direct impact of X-rays.
According to another method of recording and reproducing an X-ray pattern disclosed, e.g., in U.S. Pat. No. 3,859,527, a special type of phosphor is used, known as a photostimulable phosphor, which being incorporated in a panel is exposed to incident pattern-wise modulated X-rays and as a result thereof temporarily stores therein energy contained in the X-ray radiation pattern. At some interval after the exposure, a beam of visible or infrared light scans the panel to stimulate the release of stored energy as light that is detected and converted to electrical signals which are processed to produce a visible image. For this purpose, the phosphor should store as much as possible of the incident X-ray energy and emit as little as possible of the stored energy until stimulated by the scanning beam. This is called xe2x80x9cdigital radiographyxe2x80x9d or xe2x80x9ccomputed radiography.xe2x80x9d
Systems for computed radiography using storage phosphor technology are commercially available, e.g., under trade name ADC70, ADC Compact and ADC Solo from Agfa-Gevaert N.V., Mortsel, Belgium and under trade name FCR7000, FCR5000 and FCRAC1 from Fuji Film, Japan.
The market trend in computer radiography goes towards smaller, faster, less expensive, easy to use systems. Moreover, the need for direct access to the image, especially in medical diagnosis, is growing. Therefore, devices that are equipped with means for recording of the image made by penetrating radiation and with means for reading the image so that the recording and the reading of the image can proceed almost simultaneously are very desirable.
Systems fulfilling, at least partially, this need have been proposed and are based, e.g. on xcex1-Si detectors combined with prompt emitting phosphor layers and coupled to thin film transistors or on amorphous Se as recording medium.
Further improvement is still desired and a system combining the advantages of storage phosphor technology (a.o. high X-ray absorption) with almost direct readability of the image would be a very interesting system both for use in medical diagnosis as in non-destructive testing with penetrating radiation.
It is an object of the invention to provide a method for recording and reproducing an image made by penetrating radiation using storage phosphor technology, wherein the step of stimulating the storage phosphor and collecting the stimulated light output can be performed in a compact, quite inexpensive and sturdy apparatus.
It is a further object of the invention to provide a method for recording and reproducing an image made by penetrating radiation using storage phosphor technology, wherein the step of recording the image in the storage phosphor and the stimulating of the storage phosphor can proceed almost simultaneously.
It is still another object of the invention to provide a device comprising a storage phosphor that can be used to store energy of penetrating radiation and to stimulate the storage phosphor almost simultaneously.
Further objects and advantages of this invention will become clear from the detailed description hereinafter.
The object of the invention is realized by providing a method for recording and reproducing a radiation image comprising the steps of:
i. causing a radiation image storage panel containing a photostimulable phosphor to absorb penetrating radiation having passed through an object or having been radiated from an object,
ii. exposing said image storage panel to stimulating rays to release the radiation energy stored therein as light emission,
iii. detecting the emitted light, characterized in that said stimulating rays are emitted by an electroluminescent element.